1. Field of the Invention
The present invention relates to an objective lens unit, an in-vivo examination apparatus, and an adaptor.
2. Description of Related Art
Recently, in biological research, ion concentration, membrane potential, and so forth are visualized using fluorescence probes and optical microscopes. For example, so-called in-vivo examination (examination of internal organs and so on while the specimen is still living) is carried out using an individual laboratory animal as the specimen. With in-vivo examination, the examination site may easily shift or may become defocused because the object under examination exhibits motion such as pulsing, respiration, and so on.
One known method to eliminate such shifting of the examination site and defocusing is to use an apparatus that moves the entire microscope, including an imaging device, to track the motion of the object under examination (for example, see Japanese Unexamined Patent Application Publication No. HEI-7-222754).
However, with the apparatus disclosed in Japanese Unexamined Patent Application Publication No. HEI-7-222754, since it is necessary to drive the entire microscope, which is heavy, there is a problem in that it is not possible to move it at high speed. When examining the heart, for example, the pulse rate of a rat is about 350 beats/second and that of a mouse is about 620 beats/second. Therefore, it is extremely difficult to make the apparatus disclosed in the above-cited document track such high pulse rates.